elements = ['%{0}%'.format(element) for element in elements]
GeeksforGeeks
geeksforgeeks.org › python › python-change-list-item
Python - Change List Item - GeeksforGeeks
July 23, 2025 - Using a list comprehension, [x * 2 if x % 2 == 0 else x for x in a], we iterate over each element in the list. For each element: If the element is even (x % 2 == 0), we double it (x * 2). If the element is odd, we leave it unchanged.
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elements = ['%{0}%'.format(element) for element in elements]
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You can use list comprehension:
elements = ["%" + e + "%" for e in elements]
How do I act on each element of a list while editing it?
Generally the simplest solution to this is to create a new list rather than trying to edit the source one. Alternatively you can iterate over the list indices rather than the elements, and then pop and insert at an index to modify the elements, but that’s often not a great (or easy to follow) approach More on reddit.com
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June 10, 2023How to modify list in python
There exists also a numpy solution. ...LINK__&&__python__&&__JUMP_LINK/ ... Angelo Abi Hanna How is that different from the previous suggestions? Another way could be using list comprehension – but that actually creates a new list instead of modifying the existing one. 🤔 ... Yeah this approach is there. I come from a c++ background where reference is there for an element So curious ... More on sololearn.com
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November 29, 2023python - Modifying each element in a list in a function - Stack Overflow
I am a new programmer learning python with Codeacademy and I am supposed to create a function double_list that returns the items in list n and multiplies each number by 2. Every time I run the code... More on stackoverflow.com
python - Modify each element in a list - Stack Overflow
I thought this question was easy enough but couldn't find an answer. I have a list of tuples of length 2. I want to get a list of tuples of length 3 in which the third element is the result of some More on stackoverflow.com
How to update Elements in a List in Python - YouTube
07:54
Lists: Modifying Lists | Programming Fundamentals with Python - ...
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How to Add, Remove, and Update Lists in Python (Visually Explained) ...
11:55
Adding, removing and modifying a list | Python for Beginners | ...
02:15
How to Modify Elements in a List in Python - YouTube
00:37
Python | Modify List Item - YouTube
Codecademy
codecademy.com › forum_questions › 52320d8180ff33534f000386
Modifying each element in a list in a function | Codecademy
n = [3, 5, 7] for i in range(0, len(n)): n[i] = n[i] * 2 · def double_list(x): for i in range(0, len(n)): n[i] = n[i] * 2 return n
SitePoint
sitepoint.com › python hub › change list items
Python - Change List Items | SitePoint — SitePoint
The simplest way to modify a list element is to use its index and the assignment operator =. ... Here, we replaced the element at index 1 (the second element, since indexing starts at 0) from "banana" to "orange".
Reddit
reddit.com › r/learnpython › how do i act on each element of a list while editing it?
r/learnpython on Reddit: How do I act on each element of a list while editing it?
June 10, 2023 -
I have my answer, thanks all!
I need a better way to do this:
for element in mainlist:
split(element)
mainlist.extend(temp)
def split(element):
global mainlist, temp
#Do the splitting (I am 100% this is working correctly)
temp = [split1,split2]
mainlist.remove(element)The program is recursive, processing each part down until it is finished. (Not shown here)
In my output there are elements that are being "forgotten" after the first pass.
I assume it probably ahs something to do with remove() and "for". How do I better implement this?
Top answer 1 of 5
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Generally the simplest solution to this is to create a new list rather than trying to edit the source one. Alternatively you can iterate over the list indices rather than the elements, and then pop and insert at an index to modify the elements, but that’s often not a great (or easy to follow) approach
2 of 5
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Can you post the original problem? My general attitude toward this kind of thing is that you shouldn't have to modify the list in-place at all. Just make a new list or generator with the output.
Top answer 1 of 6
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Your function can only return once, so you need to back it out of the for loop. As written, your function currently will return x after the first iteration, so none of the remaining elements are modified.
def double_list(x):
for i in range(0, len(x)):
x[i] = x[i] * 2
return x
An alternative, by the way, is to use a simple list comprehension, this will not modify the original list and will create a new one that you can assign back to the original variable if you'd like
def double_list(x):
return [i*2 for i in x]
>>> n = [3, 5, 7]
>>> n = double_list(n)
>>> n
[6, 10, 14]
If you prefer to modify the actual list argument, you can use change the function to
def double_list(x):
for index, value in enumerate(x):
x[index] = 2 * value
>>> n = [3, 5, 7]
>>> double_list(n)
>>> n
[6, 10, 14]
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you can do it very easy with list comprehension.
n = [3, 5, 7]
def double_list(x):
return [y*2 for y in x]
print double_list(n)
'[6, 10, 14]'
GeeksforGeeks
geeksforgeeks.org › python-operation-to-each-element-in-list
Python - Operation to each element in list - GeeksforGeeks
December 19, 2024 - Let's see some other methods on how to perform operations to each element in list. ... map() function applies a function to every item in a list. We can pass a function (or a lambda) along with the list to map() and get the modified elements ...
W3Schools
w3schools.com › python › python_lists_change.asp
Python - Change List Items
To change the value of a specific item, refer to the index number.
Stack Overflow
stackoverflow.com › questions › 32769070 › modify-each-element-in-a-list
python - Modify each element in a list - Stack Overflow
September 25, 2015 - I thought this question was easy enough but couldn't find an answer. I have a list of tuples of length 2. I want to get a list of tuples of length 3 in which the third element is the result of some
Wsldp
elearning.wsldp.com › python3 › modify-list-elements-python-list
Learn How to modify list elements in Python List - e Learning
August 22, 2021 - In python 3, we use the index number of the list element to modify individual list elements. Remember that Python lists start with the index position 0, not 1.
Codecademy Forums
discuss.codecademy.com › t › 13-modify-each-element-in-a-list-in-a-function › 12109
Codecademy Forums
November 21, 2015 - Community discussion forums for Codecademy
Reddit
reddit.com › r/learnpython › how do i modify all the elements in a list without creating a new list?
r/learnpython on Reddit: How do I modify all the elements in a list without creating a new list?
April 20, 2016 -
I have a list of strings
data = ['1.2','3.4','3.5']
and I want to convert all of them to floats what I'm doing now is
indexs = []
for i in data:
i = float(i)
indexs.append(i)is there a way to do it without making an entirely new list?
Top answer 1 of 2
3
data = [float(e) for e in data] A list comprehension should do the trick. Edit: Lists are mutable, so you could change each in place. for index, value in enumerate(data): data[index] = float(value)
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Yes, but it's generally a bad idea to modify a list while you are looping over it. This is relatively safe, but don't be tempted to change the list size. for i, element in enumerate(data): data[i] = float(element) Is there any reason you don't want a new list? You could just overwrite the old list with the new one as soon as you're done making it: data = map(float, data) #python2 only; python3 makes a generator
Data to Fish
datatofish.com › modify-list-python
How to Modify an Item Within a List in Python
fish = ['salmon', 'pufferfish', 'shark'] # select element and assign value fish[0] = 'mackerel' # or use list comprehension fish = ['mackerel' if x == 'salmon' else x for x in fish] print(fish) Note that indices start at 0. The output: ... That's it! You just learned how to modify a list in Python.
Reddit
reddit.com › r/learnpython › trying to learn to modify a list with a for loop
r/learnpython on Reddit: Trying to learn to modify a list with a for loop
April 11, 2022 -
list = [1,0,1,0,1,1,0,0] print(list) for i in list:
if i == 0: i = 1
print(list)
I have a list and would like to for loop to change all of the 0s to 1s
but no changes happen
the if statement is catching the 0s but not changing them to 1s
idk why "i = 1" is not working
Reddit
reddit.com › r/learnprogramming › [python] how to change all the elements on a list?
r/learnprogramming on Reddit: [Python] How to change all the elements on a list?
July 7, 2022 -
So I have as an exercise to create a hangman type of game, so I need to change all the elements in the list (the movie name, let's say) to a "_". How can I code it?
Top answer 1 of 2
3
Python's lists are mutable objects so a quick loop running through each element would be enough to update their value to any desired character. However, after doing it, you'd lose the previous set of characters, so remember to store whatever the hidden word is in a different variable. Also, since the idea of a hangman is gradually show the letters, I feel like you should have a function to identify the correct indices which should be changed when the player guesses correctly.
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Consider a function that takes a string (the password) and a string (or set, or list) of guessed letters. For each letter in the password, check if the letter is in the guessed letters. If it is, append the character to the result. Otherwise, append an underscore. Then return the result. (This is also a great comprehension exercise) In the REPL: # Wheel of Fortune starting letters >>> hangman_word("kangaroo", "rstlne") '__n__r__'
Top answer 1 of 4
1
For the general case, use enumerate to get the index and the item. Then you can assign back to the list
for i, item in enumerate(exampleList):
if remap != item:
exampleList[i] = item + 1
remap = remap + 1
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Why would you want to do this?
print range(len(your_list))
Otherwise, use a list-comp:
print [i+1 if some_criteria(i) else 0 for i in your_list]
Top answer 1 of 4
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You could do this:
for idx, item in enumerate(list):
if 'foo' in item:
item = replace_all(...)
list[idx] = item
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You need to use the enumerate function: python docs
for place, item in enumerate(list):
if "foo" in item:
item = replace_all(item, replaceDictionary)
list[place] = item
print item
Also, it's a bad idea to use the word list as a variable, due to it being a reserved word in python.
Since you had problems with enumerate, an alternative from the itertools library:
for place, item in itertools.zip(itertools.count(0), list):
if "foo" in item:
item = replace_all(item, replaceDictionary)
list[place] = item
print item
APXML
apxml.com › courses › python-for-beginners › chapter-4-organizing-data-collections › python-modifying-lists
Modifying Python Lists | Add, Remove, Change Items
One of the defining characteristics of Python lists is their mutability. Unlike strings or tuples (which will be covered soon), elements can be changed, added, or removed from a list after it has been created. This flexibility makes lists incredibly useful for storing collections of data that might need to evolve as a program runs.